1221110121220 has 192 divisors, whose sum is σ = 2851164997632. Its totient is φ = 435617280000.

The previous prime is 1221110121113. The next prime is 1221110121229. The reversal of 1221110121220 is 221210111221.

It is a super-2 number, since 2×1221110121220² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221110121194 and 1221110121203.

It is not an unprimeable number, because it can be changed into a prime (1221110121229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1392371422 + ... + 1392372298.

It is an arithmetic number, because the mean of its divisors is an integer number (14849817696).

Almost surely, 2^{1221110121220} is an apocalyptic number.

1221110121220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221110121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1425582498816).

1221110121220 is an abundant number, since it is smaller than the sum of its proper divisors (1630054876412).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221110121220 is a wasteful number, since it uses less digits than its factorization.

1221110121220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1502 (or 1500 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221110121220 its reverse (221210111221), we get a palindrome (1442320232441).

Subtracting from 1221110121220 its reverse (221210111221), we obtain a palindrome (999900009999).

The spelling of 1221110121220 in words is "one trillion, two hundred twenty-one billion, one hundred ten million, one hundred twenty-one thousand, two hundred twenty".